You find out you need a pallet of 14 bags of seed that weigh 50 lbs each. You know the pallet itslef weighs 44lbs. The CO-OP forklift takes 30 seconds to move the pallet and bags of seed the 60 feet to the back of your truck.

A) How much power does the forklift produce to move the bags and pallet?

B) How much horsepower is needed to move the bags and pallet?

C) If the forklift were to break, how long would it take you and the CO-OP worker to move JUST

power= work/time= mgh/time

I will be happy to critique your work.

what does the mgh stand for?
on part a. i got
p=744lbs/30sec
=24.8lbs/sec but that's not the right answer....where did i go wrong?

Matt

Formula:

W = Fd kg m/s2 meters Work equals force times distance,

F = ma kg m/s2 Force equals mass times acceleration,

a = g m/s2 Acceleration is g,

F = mg kg m/s2 So force equals mass times g,

W = mgd kg m/s2 meters Which means work equals mass times g times distance,

d = h meters Distance equals height,

W = mgh kg m/s2 meters Which makes work equal to mass times g times height,

W=PE Which means potential energy it the amount of work an object could do.

mgh = (mass*gravity*height)

i think i got it
w=744*60=44,640ft-lbs

p=44,640ft-lbs/30sec
=1488ft-lbs/sec

see my post. If the 60 feet were up in the air. I read the 60 feet as horizontal. No work is done, ignoring friction.

mgh is the weight*height.

Now there is a problem with the problem. No power is used if the bags are not lifted. Just moving the bags requires no power, IF one ignores friction.
In real life, friction is considerable for a forklift, and the problem does not give any indication of that (like coefficent of friction on wheels). It did take power to lift the bags, but that is not asked in the questions.

i undertand but i guess he thinks we just assume.

In this case, if we assume that there is no friction involved and the bags are only being moved horizontally, then you are correct in saying that no power is required to move the bags without lifting them.

However, if you are asked to calculate the power required to lift the bags vertically, you can use the formula for power, which is work divided by time.

A) In this case, the work done in lifting the bags would be calculated as the weight of the bags (14 bags * 50 lbs = 700 lbs) plus the weight of the pallet (44 lbs) multiplied by the height to which they are lifted. Let's assume the height is 0 feet for now. Hence, the work done would be 744 lbs * 0 feet = 0 ft-lbs.

Since no work is done in this case, the power required would be zero as well.

B) Similarly, since there is no work being done to lift the bags vertically, the horsepower required can also be considered as zero.

C) If the forklift were to break and you and the CO-OP worker were to move just the bags without lifting them, then no power or horsepower is needed. You would simply move the bags manually.